1. Field of the Invention
Embodiments relate to a linear protection switching method in an optical transport network (OTN) system, and more particularly to, a linear protection switching method and apparatus for minimizing a data loss occurring when switching times for performing protection switching in an OTN system are different.
2. Description of the Related Art
An optical transport network (OTN) system may transport, multiplex, route, and monitor signals of a client layer in an optical domain. The OTN system may encapsulate the signals of the client layer and transmit the encapsulated signals to a layer including an optical channel transport unit (OTU), an optical channel data unit (ODUk), and an optical channel payload unit (OPUk) over an OTN. Here, k may be a value varying depending on a bit rate, for example, k=1, 2, or 3. A frame format of the OTN is defined in ITU-T Recommendation G.709, and includes an OTUk, an ODUk, an OPUk overhead, an OPUk payload area, and a forward effort correction (FEC) area.
An automatic protection switching (APS) protocol defined in ITU-T Recommendation G.873.1 may be used to perform linear protection switching in the OTN system. This Recommendation defines various linear protection switching methods in an OTN system at a level of ODUk. Further, the Recommendation describes purposes and applications of the switching methods.